Expansion plug for electric connections



Dec. 1924- 1,519,588

L. M CRACKEN EXPANSION PLUG FOR ELECTRIC CONNECTIONS Filed July 13. v1920 patented Dec. 16, 1924.

Uhlilf "LOLIE IliIoCR-l-LCKEIL 01? SANTA ANA. CALIFORNIA.

EXPANSION PLUG F855 ELECEREC GUNNECTIONS.

Application filed Pi u g:

ihis invention relates to cxpa sion plugs for electric conex and has ior its prime object the prov on of a plug tor use in connection with extension cords, and the like, which maybe si ly and quickly attached to or .letached from, an electric light socket, without the. necessity of screwing or unscrewing it, as has heretofore been the common practice.

With my improved plug, as herein shown and described, not only is the screwing and unscrewing operation avoided, but also the entangling oi the depending cord resulting from such operation, is obviated.

The details of my invention, and its function, will be fully set forth in the following specification, reference being made to the accompanying drawings forming a part thereof, and in which:

Fig. l is an elevation of the plug showing a portion in section.

Fig. 2 is similar view taken at a ri angle to the view shown in Fig. 1, and showing a portion of the casing broken away.

Fig. 3 is a fragmentary transverse section'- al elevation taken on the line 3-3 of Fig.

Fig. 4 is a transverse sectional elevation, showing the plug as applied to a standard electric light socket, parts being shown in section to display the securing means, the sectional parts taken as indicated by line d of Fig. 6.

Fig. 5 is a vertical transverse section taken on line of Fig. 6.

Fig. 6 is a top plan view.

Fig. 7 is a transverse section aken as indicated by the line 7-7 of Fig. 5.

Referring now to the drawings the numeral 10 designates a casing, constructed of metal, or any suitable material, in which a semi-cylindrical core 11 is rigidly secured by means of screws 12, or in any other appropriate manner.

A. lower hemispherical cap 13, terminating in a cylindrical portion 1 1, is secured to the lower end of the casing 10, by means or screws 15, and has a lower depending tubular portion 16, formed integral therewith,

Eerial No. 395,81 1.

through which the insulated wires 17 and pass, and which is only added to give a finished rad neat appearance to my device.

The core 1 is constructed of any suitable -C0l1lll0tlV6 material such as vulcanite, e or p aid preferably formed of two halves and 20, although this method of cot-astructionv may be altered without departure .rom the spirit of my invention; The members 19 20, of the core 1 are cut oil as at 21 and 22, respectively, to form a fiat face 23, to which a resilient plate 24 is secured, adjacent its lower edge, by means of small bolts 25, extending through holes 26 in the members 19 and E20. lt may be here noted, that the halves 19 and 20, of the core 11, are securely held together by the casing 10, and the plate 24, in addition to its normal function, serves to further secure these parts together.

The plate 24 may be constructed of any light resilient electroconductive material, and has a screw-threaded or corrugated. por tion 27, extending downwardly from its top, to conform to the size and pitch or the internal screw-threads 28 of the shell 29 in a standard electric light socket 30. Plate 24L is adapted to normally rest against the flat face 23, throughout its length.

The core 11 is reduced, as at 31, for a short distance extending oownwardly from its top to receive a screw-threaded metal split collar 32, likewise conforming to the internal screw threads 28 of the shell 29, and forming the usual means of removably attaching the plug to the socket. While I have here shown the collar to be separate and constructed of metal, it v an be seeh that suitable threads may be easily former in tegral with the core. i i hen the collar 82 is used it may be applied by cement or other well known means.

The members 19 and 20 of the core 11 are recessed as at 33 to form a seat for a vertically extending rod 34:, which is adapted to be supported in the position shown in Fig. 8 by means of a collar 35, resting on outwardly projecting ledges 36 on the portions 19 and 20. An actuating arm 37 extends outwardly from the lower end of rod 34-, at about right angles thereto, through a slot 38, in the casing 10, and has a handle secured thereon. The upper end of the rod 34: is bent to form a contact arm d0, normally resting in a recess i1 formed in the portions 19 and 20. Arm 4:0 is adapted to contact Withthe rear face of the plate 24 to spring it outwardly and effect its engagement with the shell 29 of the socket 30, in the manner of the core 11 being recessed as at let to receive such fastening means. The cap screw by which the wire 1'? is secured to the plate 4.2, also receives a wire or roe 4:6 or;- tending upwardly through an aperture 47 formed in the halves l9 and 20 of the core 11, and which connects at its upper end to a spring contact 48 mounted on the top of said core. The spring contact 48 may be secured to the core in any suitable manner, and is here shown as being attached to a metal plate 49, set in a recess 50 in the portion 19 of the core 11, by means of a cap screw 51. The wire 46 may be either directly connected to the'spring contact L8, as shown in Fig. 5, or may be secured to the metal plate 50. In a similar manner the other wire 18 is secured to a plate 52 which is fixed to the portion 20 of the plug 11 by means of a bolt 53 the bolt being set in a recess 54. The cap screw 55 by which the end of the wire 18 is secured to the plate 52 also receives one end of a wire 56 which extends upwardly through the aperture 47, and is adapted toextend through. an aperture 57 and contact with the collar 32. Thus it will be seen that elec trical contact is made by the plug when inserted in the socket 30, through the contact 48 contacting with the contact 60 of the socket 30; and the other contact being made with the shell 29 through the collar in the usual manner. v

In the operation of my device the various parts are normally in the position shown in Fig. 1, the member 2a resting against the face 23 of the core 11, and in which position the plug is ready to be inserted in the socket 30. After inserting the upper end in the socket 30, the handle 39 is moved to the right of the position shown in Figs. 1, 2 and 3, swinging the arms 40 outwardly and in contact with the rear face of plate 24:, forcing the latter outwardly and into engagement with the screw threads 28 of the shell 29, which operation wedges the collar 32 into a similar engagement around the opposite side of the socket, as clearly iilustrated in Fig. 4.

While I have here shown and described my device in its preferred form, it is understood that I reserve the right to make any modifications in the structure, as properly come within the scope of the appended claims.

Having described my invention, I claim:

1. An expansion plug for electric connections comprising a core of non-conductive material formed in two pieces, each piece having a flat face on'one side, screw threaded engaging means on the upper end of the core, extending around its arcuate side to engage the inner screw threads of a socket, a plate secured to and normally resting against and uniting the flat faces of the plug and adapted to be sprung outwardly at its top, and having corrugated portion at its top corresponding with the said screw threads on the core, a 'rod revolubly mounted on the core back of said plate, having an arm on its upper end normally resting in a recess in the core and adapted to be swung outwardly and engage the rear face of the plate to spring it outwardlyto and wedge the said screw threads into engagement with the inner screw threads of a socket, a contact plate on the top of the core, electrical conductors connecting with the said screw threaded portion and said contact plate and a casing for the lower end of the core.

2. An expansion plug for electric connections comprising a two-piece core, a contact {)lfbliQ secured to both pieces of said core and uniting the same atone end and adapted to be sprung outwardly at its other end, said core and plate being arranged to be received in a socket, and a rod revolubly mounted on the core back of said plate and adapted to engage the latter to spring it outwardly and wedge the plate in said socket.

3. An expansion plug for electric connections comprising a two-piece core and each piece having a fiat surface, a contact plate socured to both of said flat surfaces of the core and uniting the same at one end and adapted to be sprung outwardly at its other end, said core and plate being arranged to be received in a socket, and a rod revolubly mounted on the fiat surface of the core back of said plate, said rod having an arm at its upper end normally resting in a recess in the core and adapted to be swung outwardly and engage the rear face of the plate to spring it outwardly and wedge the plate in said socket.

In testimony whereof I have signed my name to this specification.

LOLIE McCRAOKEN. 

